I owned a mka. Takedown required Allen wrenches and extensions, mags are crazy expensive, and the polymer lower needed cut to put on are accessories. Also, takedown had to be perfect or you risk slamming the bolt until polymer feed ramps ruining any chance of it feeding in the future.
On the plus side, It's already "converted", ran about 70% with cheap 3 dram birdshot out of the box, and controls are just like an ar. It also takes Winchester chokes which was nice for me since I have a few Mossberg 930s.